Phosphonous and Phosphinous Amides

Phosphonous and phosphinous amides (amino organophosphines) (7.165), can be obtained from organophosphine halides by treatment with a primary or secondary amine in ether or benzene at or below room temperature. 

Et2PCl -P 2Et2NH Et2P-NEt2 -1- EtjNHJ CP RPX2 -H 4RiNH RP(NR 2 + 2RiNHJ X  

Alternatively these compounds may be obtained from dialkylamino phosphine halides by reaction with alkyl magnesium halides ((7.168) and (7.169)), aluminium alkyls ((7.170) and (7.171)) or organolithium derivatives ((7.172) and (7.173)). Phenylphosphinous chloride can be condensed with a sodium amide derivative (7.174) or a trimethylsilyl derivative (7.175) to give a phosphinous amide. 

Me2N PCI2 -P 2MeMgBr Me2N-PMe2 -P 2MgBrCl (7.168) 

Mc2N PCI2 -P 2LiBu Me2N-PBu2 -P 2LiCl (7.172) 

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The P-N bond in phosphonous and phosphinous amides is cleaved easily and quantitatively by anhydrons hydrogen chloride at room temperature (6.143) and (6.144). Dialkyl phosphines, boron trichloride or hydrogen sulphide will effect similar cleavage. 

P-N bond in phosphoramidous and phosphonamidous esters eliminating the NR2 group (9.472) and (9.478). Phosphonous and phosphinous amides oxidise on exposure to air, to give phosphonic and phosphinic amides, respectively. 

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